Let's say I have a custom fictional map create with Google maps. It is not a real place, but a custom one. Kind of like a map of the lord of the rings location, mordor or something. Working as a Google map on browser, with pins, custom image and all. Is there a way to import this to iOS MapKit to show in my own iOS app?
You could try to export the google map in KML format and then use a library to parse the KML data and view it in a MKMapView.
This seems to be useful: http://kmlframework.com